Emerald Ash Borer
Emerald ash borer (EAB), Agrilus planipennis
Fairmaire, is an exotic beetle that was discovered in southeastern
Michigan near Detroit in the summer of 2002. The adult beetles nibble
on ash foliage but cause little damage. The larvae (the immature stage)
feed on the inner bark of ash trees, disrupting the tree's ability to
transport water and nutrients. Emerald ash borer probably arrived in
the United States on solid wood packing material carried in cargo ships
or airplanes originating in its native Asia. Emerald ash borer is also
established in Windsor, Ontario, was found in Ohio in 2003, northern
Indiana in 2004, northern Illinois and Maryland in 2006, western
Pennsylvania and West Virginia in 2007, Wisconsin, Missouri and
Virginia in summer 2008, and Minnesota and New York in the spring of
2009. Since its discovery, EAB has:

Killed tens
of millions of ash trees in southeastern Michigan alone, with tens of
millions more lost in Illinois, Indiana, Kentucky, Minnesota, Missouri,
New York, Ohio, Ontario, Pennsylvania, Quebec, Virginia, West Virginia,
and Wisconsin.

EAB is not a threat to human health but it does threaten our forest and urban tree populations.
EAB is 100 percent fatal to our native ash trees of any size, any age, healthy or unhealthy, (according to research by Michigan State University and the US Forest Service).
The larva (the immature stage of EAB) spends its life inside ash trees, feeding on the inner bark where we cannot see it. This feeding disrupts the trees' ability to transport water and nutrients, causing the tree to starve and eventually die.
On its own, the beetle will only fly a few miles. However, it is easily and quickly transported to new areas when people inadvertantly move emerald ash borer larvae inside of infested firewood, ash nursery stock, and other ash items.
A tree that has been attacked by EAB can die within 2-4 years. It is estimated that more than 50 million ash trees are dead or dying in the Midwest because of this insect.
Wisconsin forests contain more than 770 million ash trees, nearly 7 percent of the tree population. In urban areas, we estimate that ash make up, on average, 20 percent of trees.